The prostaglandins are an extremely important class of unsaturated hydroxy acids found throughout the human body and implicated in many physiological processes. Studies on the biosynthesis of prostaglandins have revealed the intermediacy of bicyclic endoperoxides which exhibit tremendously enhanced biological activity. To date the major drawbacks to clinical application of these compounds have been their very broad range of physiological activity and their brief duration of action due to rapid metabolic deactivation. These factors have encouraged the synthesis of analogues possessing greater stability and more specific activity. One extremely promising approach involves the synthesis of specific prostaglandin antagonists which exhibit high affinity for prostaglandin receptors, but possess little intrinsic activity. Such compounds should help clarify the biological role of prostaglandins. We have discovered some extremely interesting new organopalladium reactions involving the addition of vinylpalladium or pi-allylpalladium compounds to strained bicyclic alkenes, and subsequent chain extension reactions employing the novel chemistry of organopalladium compounds, with which we should be able to prepare a large number of bicyclic prostaglandin analogues which will hopefully exhibit more specific activity or prove effective as antagonists. Through the use of oxymercuration and oxypalladation reactions we should also be able to prepare 7-oxa analogues of these same compounds. Many of these same reactions should also be applicable to the synthesis of naturally occurring prostaglandins of the F series and their analogues. These versatile new methods should considerably shorten present synthetic routes to known compounds and offer promise of providing a large number of new analogues which would be expected to exhibit interesting biological activity and hopefully clinical utility.